ANORTHOSITE Meaning of ANORTHOSITE in English [ ə'nɔ:θəsʌɪt ]■ noun Geology a granular igneous rock composed largely of labradorite or another plagioclase.OriginC19: from Fr. anorthose 'plagioclase' + -ite 1 . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004